Nonlinear-optical brain anatomy by harmonic-generation and coherent Raman microscopy on a compact femtosecond laser platform

Abstract

An extended-cavity Cr:forsterite laser is integrated with a photonic-crystal fiber soliton frequency shifter and a periodically poled lithium niobate spectrum compressor for simultaneous harmonic-generation and coherent Raman brain imaging. Adapting the laser beam focusing geometry to the tissue morphology is shown to enable complementarity enhancement in tissue imaging by second- and third-harmonic generation, as well as coherent Raman scattering, facilitating quantitative image analysis.